New diverging diamond interchange coming to Regina Bypass project

The Regina Bypass project will introduce another innovative intersection to a major Saskatchewan highway: the diverging diamond interchange.

Interchange should make Highway 1/Pilot Butte intersection safer

Wakabayashi said early data so far indicates the interchanges reduce traffic collisions. (U.S. Department of Highways/YouTube)

The Regina Bypass project will be using a new traffic flow measure to help merging vehicles.

The bypass will use a diverging diamond interchange to take traffic from one side of the road to the other. The system allows drivers to make left-hand turns unimpeded, essentially by having drivers merge left instead of cutting across oncoming traffic. 

"It actually is very intuitive," said Ministry of Highways spokesperson Doug Wakabayashi.

The Regina Bypass introduced the first roundabouts to Saskatchewan highways earlier this summer when a section of the bypass near Balgonie opened with the circular intersections on Highway 46.

Diverging diamond interchanges are similar to diamond interchanges, such as the one at the intersection of Ring Road and Arcola Avenue in Regina or Circle Drive and Clarence Avenue in Saskatoon.  

The new interchange will hopefully reduce accidents at the intersection of Highway 1 and the Pilot Butte access road — an area that has had a high number of fatal collisions in the past.

"Intersections are the single most dangerous point on a highway," Wakabayashi said.

He said the standard diamond interchange has about 26 conflict points — areas in an intersection with the potential for a collision. Diverging diamond interchanges reduce the number of conflict points to 14, Wakabayashi said. 

There are about 100 of the interchanges in the United States, including states like Wyoming and Colorado which experience similar weather conditions to Saskatchewan.

Typically, traffic engineers like to see several years worth of data before any conclusions are made but early data indicates the interchanges have had a positive effect, Wakabayashi said. 

"In the early years of the operation of these interchanges, some states are reporting very dramatic decreases in collisions." 

The first Canadian diverging diamond interchange was opened in Calgary this week.

Bypass progress

The Pilot Butte interchange is expected to open by the end of the next construction season in 2018.

Two overpass sections of the bypass have partially opened so far, near White City and Balgonie.

The Balgonie overpass will be fully functional by Labour Day when the remaining ramps are expected to be finished and the remaining White City ramps will be finished by the third week of September, a spokesperson for the ministry of highways said. 

The newly-paved Highway 1 east will become a four-lane highway once again by the end of September as well.

With files from CBC Radio's The Morning Edition